function [] = plotFeatures( training_output )
    % the matrix is a 3X3 matrix
    % columns represent features
    % rows represent classes
    
    [train_rows, train_columns] = size(training_output);
    colors = ['b', 'g', 'r'];
    titles = {'Area of convex hull', 'Convex hull points' ,'Strongest points'};
        
    % plot each feature
    for i =1 : train_columns
        figure;
        for j = 1 : train_rows
            h = histfit(training_output{j ,i});
            % set the title of each windows respectively
            title(titles{i});
            % set colors used
            set(h(1), 'facecolor', colors(j));
            set(h(2), 'color', 'k');
             % wait to draw again in the same window
            hold on;
        end
    end
end